This application claims the benefit of Japanese Application No. 2001-334148 filed Oct. 31, 2001.
The present invention relates to an X-ray generating apparatus and more particularly to an X-ray generating apparatus using an X-ray tube.
In an X-ray generating apparatus using an X-ray tube there is performed X-ray shield lest X-ray generated by the X-ray tube should leak to the exterior except the X-ray portion to be radiated to an object. Lead is used for the X-ray shield.
In an X-ray generating apparatus of an integrate type in which an X-ray tube is received within a single container together with a high voltage circuit which is for the supply of electric energy to the X-ray tube, X-ray shield is effected, for example, by affixing a lead plate cylindrically to an outer surface of the X-ray tube except an X-ray emitting surface portion. The affixing of the lead plate is performed using an epoxy resin for example.
The interior of the container with the X-ray tube and the high voltage circuit received therein is filled with an electrically insulating liquid, and heat generated from the X-ray tube is transmitted through the liquid to walls of the container and is radiated to the exterior from the container walls.
In the X-ray tube with the lead plate affixed to the outer surface thereof, the generated heat cannot efficiently be transmitted to the surrounding liquid because the thermal conductivity of lead is not so high and further because an epoxy resin is interposed between the outer surface of the X-ray tube and the lead plate which epoxy resin is much lower in thermal conductivity than metal.
Therefore, it is an object of the present invention to provide an X-ray generating apparatus having an X-ray shielding means superior in thermal conductivity.
(1) In one aspect of the present invention for solving the above-mentioned problem there is provided an X-ray generating apparatus comprising an X-ray tube, an X-ray tube container constituted by copper alloy plates with lead incorporated therein, the X-ray tube container having an aperture for the emission of X-ray and containing the X-ray tube so as to prevent the emission of X-ray from any other portion than the aperture, and a support member formed of an electrically insulating material and supporting the X-ray tube within the X-ray tube container.
According to the above aspect (1), since the X-ray tube container is constituted by copper alloy plates with lead incorporated therein, it is possible to provide an X-ray generating apparatus having an X-ray shielding means superior in thermal conductivity.
For enhancing the X-ray shieldability it is preferable that opposed faces of adjacent the copper alloy plates have each an inclination intersecting the direction of X-ray radiated from the X-ray tube.
(2) In another aspect of the present invention for solving the foregoing problem there is provided an X-ray generating apparatus comprising an X-ray tube, an X-ray tube container constituted by a combination of copper alloy plates with lead incorporated therein and a plate of a composite material, the composite material being formed by laminating lead and epoxy laminated glass cloth sheets so as to include an intermediate layer of lead, the X-ray tube container having an aperture for X-ray emission and containing the X-ray tube so as to prevent the emission of X-ray from any other portion than the aperture, and a support member formed of an electrically insulating material and supporting the X-ray tube within the X-ray tube container.
According to the above aspect (2), since the X-ray tube container is constituted by a combination of lead alloy plates and plates of a composite material each formed by laminating lead and epoxy laminated glass cloth sheets so as to include an intermediate layer of lead, it is possible to provide an X-ray generating apparatus having an X-ray shielding means superior in thermal conductivity.
For enhancing the dielectric strength of the X-ray tube container it is preferable that a portion of the X-ray tube container relatively far from the X-ray tube be constituted by the copper alloy plates, while a portion of the X-ray tube container relatively close to the X-ray tube be constituted by the plates of the composite material.
For improving the X-ray shieldability it is preferable for the copper alloy plates and the plate of the composite material to be arranged so that opposed faces of adjacent ones have each an inclination intersecting the direction of X-ray radiated from the X-ray tube.
For making X-ray shieldability and thermal conductivity compatible with each other it is preferable that the proportion of lead in the copper alloy be in the range of between 21% and 26%.
For improving the X-ray shieldability it is preferable that the copper alloy plates have a thickness of at least 6 mm.
For improving the X-ray shieldability it is preferable that the thickness of the intermediate layer in the plate of the composite material be at least 2 mm.
According to the present invention, there can be provided an X-ray generating apparatus provided with an X-ray shielding means superior in thermal conductivity.
Further objects and advantages of the present invention will be apparent from the following description of the preferred embodiments of the invention as illustrated in the accompanying drawings.